Entomology (Study of Bugs)/3 inch worm lol


3 inch worm?
3 inch worm?  
QUESTION: So my Aunt found this wandering on the patio so she put it in the garden. It moved faster than she could move the tape. Green, wormlike, and about 3 inches. What is this?

ANSWER: Dear Douglas - This is a caterpillar of a moth in the family Saturniidae (giant silk moths). I believe that it most likely is that of a polyphemus moth, Antheraea polyphemus - see http://tinyurl.com/qz9z5jr for images and more detailed information.

Hope this helps,

---------- FOLLOW-UP ----------

QUESTION: So is this the same as a Luna moth caterpillar, or is there a difference bewteen a luna moth caterpillar and the polyphemus moth caterpillar. If different please explain the differences.

Dear Douglas - The caterpillars of these two species are indeed quite similar, a fact compounded by both showing a good deal of individual variation. One key difference is that the abdominal segments of polyphemus caterpillars have a vertical yellow line that passes through/over their spiracles, about in the middle of each segment; these can be seen in your specimen. In Luna moth caterpillars, the vertical yellow line is at the far rear of each segment. Additionally, Luna caterpillars usually have a pale horizontal line (sometimes quite faint) that passes under the spiracles - see http://tinyurl.com/zgduwhl for an image.

Hope this helps,

Entomology (Study of Bugs)

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Ed Saugstad


Will accept most questions in general entomology, including those related to medical entomology, taxonomy, ecology, arthropod surveillance, and pest management. If you are requesting a 'mystery bug' identification, PLEASE either attach an image to your question, or post an image on a web page (such as Flickr) so that I can look at it, as verbal descriptions frequently are insufficient for a definitive identification.


21 years in the U.S. Army as a medical entomologist; duties varied from surveillance of pest populations (including mosquitoes, cockroaches, ticks, and stored products pests) to conducting research on mosquito-virus ecological relationships and mosquito faunal studies. Ten years as a civilian analyst for the Department of Defense, primarily on distribution of vector-borne diseases worldwide. Limited experience on surveillance of agricultural insects in North Dakota and Indiana.

Entomological Society of America, West Virginia Entomological Society, Society for Vector Ecology, National Speleological Society, West Virginia Association for Cave Studies.

American Journal of Public Health, Contributions of the American Entomological Institute, Japanese Journal of Sanitary Zoology, Journal of Economic Entomology, Mosquito News, and Mosquito Systematics.

B.S. in entomology from North Dakota State University in 1963, M.S. in entomology from Purdue University in 1967.

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